Serious Champ move idea: A suicide type attack where they channel for 3 seconds and do extreme dmg

in an aoe around them.

Here's how it would work, they start the channel for 3 seconds, during those 3 seconds they are invulnerable and cannot be displaced. After the 3 seconds they blow up in a semi large aoe(think ziggs ult) and do extreme damage to everybody in the circle.

HOWEVER

Whoever hit this champ last will get the reward for the kill, it can't deny kills like techies in Dota2.

Edit: The champ would be rooted while channeling.